This project involves the isolation and characterization of erythrocyte membrane Band 3 glycoprotein using lectin affinity chromatography procedures from controls and patients with myotonic muscular dystrophy (MyD). Previous studies have demonstrated a decreased (32P)-phosphorylation of a specific species of Band 3 glycoprotein in MyD patients. Peptide mapping procedures using both gel techniques and high pressure liquid chromatography are planned. Efforts are aimed at delineating a unique (32P)-peptide or an alteration in the stage of phosphorylation of a specific peptide of MyD Band 3. Multiple hydrolysis techniques are being studied, as well as multiple peptide mapping techniques. In addition, recent data have directed studies to the interrelationship of the polyphosphatidyl inositols to Band 3. Calcium stimulated tri- and diphosphotidyl inositol phosphodiesterase activity is being studied in MyD erythrocyte membranes.